intro and conventional bridgework

Question 1

What are the reasons for treating tooth loss?

Answer 1

Aesthetics
Function
Speech
Maintenance of dental health - adjacent teeth can tilt or overlap

Question 2

What is a bridge?

Answer 2

A prosthesis which replaces a missing tooth or teeth and is attached to one or more natural teeth or implants

Question 3

What is the difference between adhesive bridges and conventional bridges?

Answer 3

Adhesive bridges have palatal wings
Conventional bridges are held on by crowns

Question 4

Name 4 general indications for bridgework

Answer 4

Any from:
- function and stability
- appearance
- speech
- psychological reasons
- systemic disease
- cooperative patient with good oral hygiene

Question 5

Name 4 local indications for bridgework

Answer 5

Big teeth
Heavily restored teeth
Favourable abutment angles
Favourable occlusion

Question 6

Name 4 general contra indications for bridgework

Answer 6

Any from:
- uncooperative patient
- MH contraindications eg - metal allergy
- poor oral hygiene
- high caries rate
- periodontal disease
- large pulps - in young patients

Question 7

Name 4 local contraindications for bridgework

Answer 7

Any from:
- high possibility of tooth loss in future
- poor prognosis of abutment
- length of span too great
- ridge form and tissue loss - replicating gingiva is difficult
- tilted and rotated teeth
- endodontic disease
- periodontal disease

Question 8

What is an abutment?

Answer 8

A tooth which serves as an attachment for a bridge

Question 9

What is a pontic?

Answer 9

An artificial tooth which is suspended from the abutment tooth

Question 10

What is a retainer in bridgework?

Answer 10

The extra-coronal or intra-coronal restorations that are connected to the pontic and cemented to the prepared abutment teeth

Question 11

What are connectors in bridgework?

Answer 11

Component which connects the pontic to the retainer

Question 12

What is the edentulous span?

Answer 12

The space between natural teeth that is to be filled by a bridge or partial denture

Question 13

What is a saddle?

Answer 13

The area of the edentulous ridge over which the pontic will lie

Question 14

What is a pier?

Answer 14

An abutment tooth which stands between and is supporting two pontics, each pontic being attached to a further abutment tooth

Question 15

Describe a unit in bridgework?

Answer 15

Either a retainer or a pontic eg - a bridge with two retainers and one pontic = 3 unit bridge

Question 16

Describe the different types of conventional bridges

Answer 16

Fixed-fixed - retainers at either side
Fixed cantilever - retainer only at one side
Fixed movable - fixed connector distally and movable connector mesially

Question 17

Name 3 uncommon bridge designs

Answer 17

Fixed-movable bridge
Hybrid bridge
Spring cantilever bridge

Question 18

Name 3 advantages of conventional fixed-fixed bridges

Answer 18

Robust
Maximum strength and retention
Abutment teeth can be splinted together in perio cases
Can be used in longer spaces
Lab construction is straightforward

Question 19

Name 3 disadvantages of conventional fixed-fixed bridges

Answer 19

Prep difficult (parallel tooth preps needed)
Prep must be minimally tapered
Common path of insertion for abutments is difficult
Removal of tooth tissue causes danger to pulp

Question 20

Describe the ideal taper in a conventional fixed-fixed bridge and the disadvantage of overtaper

Answer 20

Aim for 5-7º
Can go as far as 10º
If overtaper, crown can slide off in multiple directions

Question 21

Describe a fixed movable bridge

Answer 21

Bridge in 2 parts - crown, pontic and dovetail, then separate crown with slot for dovetail. Uses two paths of insertion

Question 22

Name 3 advantages of a conventional fixed-moveable bridge

Answer 22

Any from:
- prep doesn’t require a common path of insertion
- each prep is designed to be retentive independent of others
- conservative of tooth tissue
- allows minor tooth movement
- may be cemented in two parts

Question 23

Name 3 disadvantages of fixed-moveable bridges

Answer 23

• length of span limited
• lab construction complicated
• difficulty in cleaning beneath moveable joint
• can’t construct provisional
• need patient with good oral hygiene

Question 24

Name 3 advantages of conventional cantilevered bridges

Answer 24

Conservative design
Lab construction straightforward
No need to ensure multiple tooth preps are parallel

Question 25

Name 3 disadvantages of conventional cantilever bridges

Answer 25

Short span only
Rigid to avoid distortion so prone to fracture
Mesial cantilever preferred as abutment teeth more posterior are likely to occlude first

Question 26

Describe a hybrid bridge

Answer 26

Rarely see these
One retainer is conventional prep, the other retainer is minimal prep
Metal wing likely to debone, not noticeable which leads to leakage

Question 27

Describe a spring cantilever bridge

Answer 27

Rarely see these
One pontic attached to the end of a metal arm that runs across the palate to a riding connector on the palatal side of a retainer

Question 28

Name 2 advantages of a conventional spring cantilever bridge

Answer 28

Any from:
- useful if spacing present between upper incisors
- do not need to restore adjacent teeth
- useful if posterior already has a large direct/indirect restoration

Question 29

Name 2 disadvantages of conventional spring cantilever bridges

Answer 29

Any from:
- can only be used to replace upper incisors
- difficult to clean beneath palatal connector
- may irritate the palatal mucosa
- difficult to control movement of pontic due to springiness of metal arm and displacement of palatal soft tissues

Question 30

What makes a good abutment tooth for a bridge?

Answer 30

1. Must be able to withstand the forces previously directed to the missing teeth
2. Supporting tissues should be healthy and free of inflammation
3. Crown to root ratio optimally 2:3, minimally 1:1